The present invention relates to a process for the biocatalytic coupling of aromatic compounds such as phenols, thiophenols and anilines and, particularly, to a process for coupling sterically hindered aromatic compounds in the presence of a peroxidase enzyme, a peroxide and a radical transfer agent to provide the corresponding dimer.
The biocatalytic oxidative coupling of phenols using horseradish or soybean peroxidase is disclosed in U.S. Pat. No. 4,900,671 to Pokora et al. and U.S. Pat. No. 5,188,953 to Johnson et al. The dimerization of dialkyl and diarylphenols such as 2,4-dialkylphenol and 2,6-dialkylphenol is discussed in copending U.S. application Ser. No. 08/379,202 filed Jan. 27, 1995.
Klibanov et al. "Enzymatic Removal of Toxic Phenols and Anilines from Waste Waters" J. of Appl. Biochem. 2, 414-421 (1980) teaches the horseradish peroxidase-assisted polymerization and precipitation of phenols and anilines from waste water and further discloses that the removal of some phenols which are difficult to remove from waste water can be enhanced by the presence of other easily removable phenols. The products are considered to be mixed polymers containing both hard to remove phenols and easily removable phenols.